Heretofore, or at least up to the advent of the present invention, there has been a desideratum for precision slide assemblies for use in many applications which require, for example, "in line" movement of machine parts. The requirements of negligible friction and wear to overcome problems of binding and shake, which are normally associated with conventional slide apparatuses, have continually been a matter of difficulty and concern of designers and engineers.
Some conventional slide units incorporate linear ball bearings into compact assemblies combining hardened contact surfaces for minimum wear, rolling elements for low friction, and minimum or zero backlash. Some of such units contain integral seals to exclude foreign matter and retain lubricant. On the other hand, some of such units are available without such seals.
Some of the conventionally-available units consist of a single hardened slide bar having a flat surface ground over its full slide length, two in-line linear ball bearings, and an eccentrically adjustable roller bearing, all assembled into a compact housing. The ends of the slide bar may be provided either with plain ends or with flat square surfaces to facilitate mounting of tools and actuating links. Such slide units combine the compactness of a single slide bar with a feature for eliminating a substantial amount of play or shake between the rolling elements. This is accomplished by means of an eccentric pin and roller bearing contacting the flat surface of the slide bar, and results in the prevention of most, if not all, rotation or play. The housing may incorporate a central lubricating oiler, seals, and mounting holes. Such slide units may be used in applications where compactness, minimum shake, or pre-load of rolling elements is required.
However, where added flexural rigidity and heavier load capacity is required, a two slide bar apparatus may be employed, and is commercially available.
The aforementioned two slide bar units incorporate two slide bars secured rigidly at both ends by plates and passing through two sets of linear ball bearings which are mounted in a housing. Such end plates will permit the mounting of actuating links or tools, or may serve as fixed supports when the housing assembly is used as the sliding member.
Tools or machine parts which require in-line motion may be mounted to such aforementioned conventional slide units either on the surfaces provided at the slide bar ends, or on the housing when the slide bar ends are fixed thus permitting the housing to move. Such conventional slide units may also be used in pairs where off-center loading or actuation does not present the problems associated with conventional dovetails or sleeve bushings.
Without dwelling on a plethora of animadversions concerning the prior art slide mechanism discussed hereinabove, suffice it to say that such mechanisms are inert and require separate devices to operate them. In other words, it is necessary to attach pneumatic, hydraulic, and/or mechanical devices to such conventional slide apparatuses in order to achieve and control the desired movement. However, in many cases and applications there are serious space and clearance problems involved in attempting to interrelate all of the parts, tools and mechanisms required to accomplish the total desired function. It is a primary object of the present invention to accomplish such a result at a minimum of costs, and parts, by providing a slide apparatus which is actuated by a self-contained internal fluid power mechanism.